Brush for generators, etc.



Patented Apr. 3, 1928.

UNITED STATES MICHIGAN, ASSIGNOR '10 FBEDEBICKSEN' COM- ARTHUR A.sonurr, F SAGINAW,

PATENT OFFICE.

.nausn non GENERATORS, are.

No Drawing. Application filed April 2,

This invention relates to brushes for electric generators and motors andpertains more particularly to a brush made of an alloy and comprising anew article of manufacture.

The objects of my invention are to make a brush of such composition thatit will have greater density and consequently less electrical resistancethan brushes made by baking the oxide of metals in the presence of adeoxidizer.

A further object is to produce a metallic brush that will beself-lubricating and also inexpensive to manufacture.

Brushes of this kind have been heretofore made in practice from amixture of the oxides of copper, tin, lead etc. with graph-v ite. themixture pressed into solid form and then baked in the presence of adeoxidizer. This results in a somewhat porous brush structure. 1

My improved brush is denser and has less electrical resistance. It ismade of a mixture of approximately equal parts of metallic copper andmetallic lead. These two metals are melted together and then eithermolded into brushes by die or sand casting, or casting 1 not less thanabout per cent lead, and

in permanent molds, or formed into a bar by extruding, the bar beingsubsequently sheared to the desired length for brushes.

The proportions may vary within reason- 1924. Serial No. 703,779.

able limits from the above quantities, but the mixture should containmore than forty per cm; copper and more than forty per cent lea The leadmakes the completed brush prac- 35 tically self-lubricating.

I am aware that various mixtures of lead and copper have been made forother purposes, but I am not aware that an alloy of these two metals inthe proportions specified 4 has been used for the production ofselflubricating generator and motor brushes. My method avoids the use ofmetallicoxides, the baking furnace and the deoxidizer.

Having thus described my invention, what I claim and desire to secure byLetters Patent 15: I I

1. As an article of manufacture, a brush made of a cast metal alloyconsisting of metallic lead and metallic copper in substantially equalproportions.

2. An electrical commutator brush composed'of an alloy of copper andlead, with not less than about 40 per cent lead.

3. An electrical commutator brush, com- )osed of an alloy of copper andlead, with substantially free from carbon or graphite.

In testimony whereof, I aflix my signature. ARTHUR A. SOHUPP.

